Secretin

Secretin (ChiRhoStim) is a real, FDA-approved 27-amino-acid diagnostic peptide hormone used to test pancreatic function and help diagnose gastrinomas — and a genuine cautionary tale, since it was also chased for years as an unproven autism treatment that controlled trials repeatedly found didn't work.

What it's actually approved for

Secretin is a 27-amino-acid peptide hormone; the FDA-approved products are synthetic diagnostic agents, not treatments. Intravenous secretin stimulates pancreatic exocrine secretion (fluid and bicarbonate), used to evaluate pancreatic exocrine function. Separately, in the "secretin stimulation test," it's used alongside serum gastrin measurement to help diagnose Zollinger-Ellison syndrome: secretin paradoxically stimulates gastrin release from gastrinoma tissue (unlike normal gastrin-producing cells, which it suppresses), so a significant rise in gastrin after secretin injection points toward a gastrinoma. It's also sometimes used to help locate the ampulla of Vater during ERCP procedures.

The autism controversy — and what the trials actually found

In the late 1990s, an uncontrolled case report describing apparent improvement in three autistic children who happened to receive secretin during an unrelated GI workup triggered a wave of off-label use of secretin as an autism "treatment." A rigorous rebuttal followed quickly: Sandler et al. (N Engl J Med 1999, PMID 10588965) ran a double-blind, placebo-controlled trial in 60 children with autism or pervasive developmental disorder and found no benefit at four weeks. A subsequent review of the accumulated evidence found that essentially all of the double-blind, placebo-controlled trials conducted — more than a dozen — failed to show secretin worked for autism. This is a genuinely useful case study for a site built around distinguishing real evidence from hopeful anecdote: a real, FDA-approved diagnostic drug, chased for years as a treatment for a condition it was never studied or approved for, and controlled trials found it didn't work.

Current status

ChiRhoStim (synthetic human secretin, ChiRhoClin) is the currently marketed FDA-approved product, first approved in 2004. An earlier synthetic porcine-secretin product, SecreFlo, was discontinued around 2009 after its distributor's licensing agreement lapsed. No grey-market or wellness-market presence — this is a diagnostic-only hospital/clinic agent.